System and method for a communication network

ABSTRACT

The invention proposes a method and system for handling transmission of packets and/or signalling in a system including a node, e.g. SGSN, for transmitting data packets and/or signalling to another entity or receiving data packets and/or signalling from the another entity, e.g. GGSN. The node has a distributed architecture which includes at least two processing units each having their own address or identifier and being able to transmit and/or receive packets and/or signalling to or from the another entity. The node is adapted to send, in case one or more of its processing units is at least temporarily no longer usable or to be used for sending or receiving packets and/or signalling, information to the another entity for informing the another entity thereon. The information sent from the node to the another entity may contain an address or identifier of another processing unit to be used for receiving and transmitting packets and/or signalling instead of the processing unit no longer to be used.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a system and method for handlingconnection information in a communication network.

The field of the invention is preferably related to a GSM/UMTS system ormethod, in particular to a method or, system which includes one or morenetwork entities, preferably GTP entities, e.g. support nodes, forinstance GSNs (GPRS Support Nodes) such as SGSNs (Serving GPRS SupportNodes), and RNCs (Radio Network Controllers). Such network entities arecapable of exchanging packet or signalling through logical connections(e.g. GTP tunnel).

In some cases, it may be preferable that a support node such as RNC,SGSN, or GGSN (Gateway GPRS Support Node), has distributed architecture.

Distributed architecture of a GTP entity node such as SGSN, GGSN, or RNCmeans that several computer units (e.g. packet processing units, orcontrol plane processing units) are provided to take care of user packetrouting towards and from another GTP entity. If one of the unitsinterrupts operation because of breakdown, maintenance purpose, reset orthe like, the GTP entity, e.g. SGSN, is still capable to transmit userpackets to, or receive packets from, the another GTP entity, via theother internal units. The GTP entity is thus more fault-tolerant forpossible hardware breakdowns or the like.

SUMMARY OF THE INVENTION

According to one aspect, the invention provides a system as defined inthe independent system claim.

According to a further aspect, the invention provides a method asdefined in the independent method claim.

The invention allows support of partial reset of an entity, preferably aGTP entity such as RNC, SGSN and GGSN, having distributed architecture.

According to one of the preferred aspects, the invention provides apossibility for a first entity, in particular a GTP entity, e.g. SGSN,to inform another entity such as another GTP entity, e.g. RNC, GGSN orSGSN, which one(s) of its control or user packet processing unitsidentified by e.g., IP address and/or identifier such as TEID (TunnelEndpoint Identifier) values or logical name have been reset, or it maynotify another GTP entity that the PDP contexts handled by one of itspacket processing units have been taken over by another unit (identifiedby e.g., IP address and/or identifier such as TEID values).

This allows another GTP entity to make necessary actions to attachedsubcribers or given PDP contexts. A GTP entity such as GSN whichpartially resets may send a GTP message to another GTP entity such asGSN with information about the packet processing unit (e.g. IP-addressof that unit and TEID values). Alternatively, a GTP entity (RNC, SGSN)which partially resets may send a RANAP message to RNC or SGSN withinformation about the packet processing unit (e.g. IP-address of thatunit and TEID values).

The TEID values are preferably defined by a TEID range, such as all TEIDstarting by 10101.

If, for a processing unit (with one IP address), some but not all PDPcontexts are lost, and only IP address of this processing unit is usedto indicate this fact, all PDP contexts of this processing unit have tobe removed or cancelled. When, in accordance with some of theembodiments of the invention, identifier such as TEID values is used toreport, the PDP contexts to be removed can be individually indicated.Hence, not all but only the indicated PDP contexts of the processingunit can be removed while the other PDP contexts can still be used.

In case another packet processing unit in RNC or GSN is to take overhandling of the PDP contexts, the information about the packet procesingunit (e.g. IP address of that unit) shall also be indicated in themessage.

In turn GTP entity, e.g. GGSN, can delete all PDP contexts that wereserved by the reset unit in another GTP entity, or it may update its PDPcontext database with the identity of the new packet processing unit.With this message GTP entity can distinguish between whole GTP entityreset (e.g. SGSN system reset) and special packet processing unit reset.

In more detail, the invention provides a method and system including afirst entity for transmitting data packets and/or signalling to anotherentity or receiving data packets and/or signalling from the anotherentity, the first entity having a distributed architecture whichincludes at least two processing units each having their own address oridentifier and being able to transmit and/or receive packets and/orsignalling to or from the another entity, the first entity being adaptedto send, in case one or more of its processing units has become at leasttemporarily unusable, or is at least temporarily not to be used, forsending or receiving packets and/or signalling, information to theanother entity for informing the another entity thereon.

The invention is applicable to user plane and/or to the control plane.The processing unit reset mechanism is applicable to packet processingunit reset, and also to the control plane, e.g. signalling processingunit reset. Hence, the invention is providing to maintain logicalconnection including signalling connection and packet exchanging.

The address may be an IP address.

The identifier can be a Tunnel Endpoint Identifier (TEID), or a logicalname, and this logical name is preferably exchanged between said firstand another entity during connection creation or modification.

The first entity can be a GTP entity, e.g. a support node, preferably aGPRS support node, preferably a SGSN.

The another entity also may be a node, preferably a support node,preferably a GPRS support node, preferably a GGSN.

The information sent from the first entity to the another entity can bea GTP message.

The information sent from the first entity to the another node maycontain the address of the processing unit which is at least temporarilyunusable or not to be used.

The information sent to the another entity may include the identifier ofthe unusable processing unit(s) which is at least temporarily unusableor not to be used.

The information sent to the another entity may include the address ofthe first entity and the identifier(s) of the unusable processingunit(s).

The information sent from the first entity to the another entity maycontain indication of another processing unit to be used for receivingand transmitting packets and/or signaling instead of the processing unithaving become at least temporarily unusable.

The first entity may maintain in a protected memory the addresses of allsaid another entities it is connected to, and is adapted to send, incase one or more of its processing units has become at least temporarilyunusable, or is at least temporarily not to be used, for sending orreceiving packets and/or signalling, information to all the said anotherentities stored in its said memory, for informing the another entitiesthereon.

The processing units may be packet processing units.

The invention can be implemented in a packet-switched network such as aGSM-GPRS or UMTS network, in a circuit-switched network, or may consistof a combination of networks of different type.

The system may consist of a whole network, may be only a part of anetwork including only the network entity, e.g. support node, having thedistributed architecture, and the another entity, or may comprise two ormore networks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a basic structure of one embodiment of a system inaccordance with the invention;

FIG. 2 illustrates an example of a message flow between support nodes ofa network in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 shows a basic structure of one embodiment of a communicationsystem in accordance with the invention. Only GTP entities are shownwhich in this embodiment are implemented as GPRS support nodes GGSN 1,SGSN 2. The GTP entities may also be implemented as RNCs (Radio NetworkControllers) or network entities of other type, having distributedarchitecture. Other necessary or optional components such as radioaccess network, user equipments or mobile or fixed stations (calloriginating or terminating entities), control entities and other basicnetwork structures or other networks such as PTSN, PDNs etc. are knownto the person skilled in the art and are not shown.

FIG. 1 shows the distributed architecture of the SGSN 2. The SGSN 2includes a plurality of (at least two) processing units which may besignalling processing units. In the present embodiment, the processingunits are implemented as packet processing units 3, 4, 5, 6. In theshown embodiment, four packet processing units are provided. The numberof (packet) processing units may be different therefrom, e.g. two,three, or more than four (five, etc.). The packet processing units arepacket routing units for routing packets between the SGSN 2 and the GGSN1, and may be implemented as computer units.

In this embodiment, all of the packet processing units 3 to 6 have theirown IP-addresses IP address1, to IP address4, as shown in FIG. 1.

All packet processing units 3 to 6 of the SGSN 2 can normallyindependently of each other communicate with the GGSN 1 as shown bylines in FIG. 1.

GGSN 1 comprises, or cooperates with, a database which includes PDPcontexts. The PDP contexts in the database include the identities, e.g.addresses such as IP addresses, of the packet processing units 3 to 6 ofthe SGSN 2 which are able to transmit and receive data packets to andfrom the GGSN 1. The GGSN 1 can create or update new PDP contexts when anew data processing unit of the SGSN 2 is able to transmit and receivepackets to and from the GGSN 1. Further, the GGSN 1 can delete PDPcontexts related to a packet processing unit of the SGSN 2 which is nolonger to transmit and receive packets to and from the GGSN 1, e.g.caused by a reset of this unit.

In accordance with the invention, the support node having thedistributed architecture, that is the SGSN 2 in this embodiment, isimplemented to be able to inform another support node in communicationtherewith, that is the GGSN 1 in this embodiment, that one (or more) ofits packet processing units 3 to 6 are out of order, e.g. have beenreset, or it may notify GGSN 1 that the PDP contexts handled by one ofits packet processing units 3 to 6 has been taken over by another unit 3to 6 (identified by the IP address). This allows GGSN 1 to performnecessary actions to those subcribers that are attached.

The SGSN 2 preferably sends a message, e.g. a GTP message (e.g. controlplane, or a signalling GTP message), to the GGSN 1 which messageincludes information about the presently at least temporarily unusablepacket processing unit (IP-address of that unit). In case there isanother packet processing unit in SGSN 2 to take over handling of thePDP contexts handled by the now unusable unit up to then, the IP addressof the new-unit is preferably also indicated in the message to the GGSN1. In turn GGSN 1 can delete all PDP contexts that were served by thereset SGSN packet processing unit, or it may update its PDP contextdatabase with the identity of the new serving SGSN packet processingunit. With this message from the SGSN 2 informing the GGSN 1 on anunusable, i.e. presently no longer usable unit 3 to 6, the GGSN 1 canmake a difference between whole SGSN system reset and special packetprocessing unit blocking or reset allowing continued use of the SGSN viastill functioning units.

FIG. 2 illustrates the functioning and message flows in an embodiment ofthe invention which may have the structure shown in FIG. 1. The SGSN 2is implemented to detect, or to be informed, (e.g. by a packetprocessing unit resetting means) if one or more of its packet processingunits is presently unusable, e.g. after reset, and is thus at leasttemporarily not usable or to be used. When the SGSN 2 detects, or isinformed on, such a situation, it sends a message to the GGSN 1 whichmessage indicates the address of the presently unusable packetprocessing unit. The GGSN 1 reacts in an appropriate manner, e.g. byGGSN deleting the PDP Context(s) assigned to the presently unusablepacket processing unit. As optional feature, the GGSN 1 may send aconfirmation to the SGSN 2 for confirming the receipt of the messagefrom the SGSN 2.

GGSN 1 preferably maintains a pointer to the serving SGSN unit at eachPDP context record to provide an association between contexts and SGSNunits.

Preferably, GTP protocol is used between SGSN and GGSN. The inventionprovides a mechanism that allows SGSN to inform GGSN that only one (ormore up to all) of its processing units has been reset or is at leasttemporarily no longer usable. The distributed packet and/or signalinghandling in SGSN can therefore be continued despite partial reset.

This embodiment of the invention allows to distinguish between totalnode, e.g. SGSN, reset and partial node, e.g. SGSN, reset, i.e. packetprocessing unit resets, the partial reset allowing continuedcommunication between the node, e.g. SGSN, and another node, e.g. GGSN.The invention thus provides means to restrict e.g. the number of PDPcontexts to be deleted in GGSN in case of a partial reset in SGSN to amore reasonable .extent.

In another embodiment of the invention, a node, e.g. a GTP node such asSGSN, RNC, GGSN, may have only one IP address but many processing units(typically referred to as clustering). In this case, each processingunit is uniquely identified by the combination of the IP address and anidentifier. A first preferred option is that this identifier is a rangeof TEID. This is particularly suitable if the node uses the TEID todistribute the traffic among its processing units. In the GTP protocolsTEIDs are exchanged during the establishment or modification of the GTPtunnel. In a second option, this identifier is a logical name allocatedby each node to its processing units, such as “processing unit1”. Thenthis option of the invention includes the feature of exchanging duringthe GTP tunnel establishment or modification, a processing unit logicalname, identifying the processing unit together with the IP address ofthe node. This option presents the advantage of maintaining a logicalindependence between mechanism used to identify a GTP tunnel end pointand reset mechanism.

Then, in case of a partial reset, the node will initiate a resetprocedure indicating, to another node, the processing unit identifieri.e. logical name or TEID values identifying the processing unit(s) tobe, or having been, reset, in addition to the IP address of the node.The another node receiving the reset message will mark the one or allthe relevant PDP contexts (or RAB contexts) having both IP address andprocessing unit identifier or TEID values with the IP address, asinvalid. Depending on the case, the another node may either reestablishthe context (e.g. sending new RAB establishment) or deactivate the PDPcontext.

In addition, if the clustered node (i.e. the node having many processingunits, e.g. a GGSN) preferably stores in a protected memory the list ofnodes(e.g. SGSN) it is connected to. In case of partial reset, the GGSNreset process will access this memory and send a reset message to allthe nodes (SGSN) stored in this memory.

Generally, GTP protocol is used between SGSN and GGSN, and RANAPprotocol is used between SGSN and RNC. The protocol used fortransmitting the identifier can thus be GTP or RANAP protocol, or anyother suitable protocol.

Similarly, the protocol used to carry the reset message may be GTP orRANAP protocol, or any other suitable protocol.

Basically, GTP tunnels are established/modified using RAB establishmentprocedure over Iu interface, and create or update PDP context messagesare sent over Gn/Gp interface.

Thus, the embodiments of the invention provide a solution not only forGn/Gb (or Gp) interfaces but also for Iu interface.

Although preferred embodiments have been described above, the inventionis not limited thereto and may also be implemented in networks ofdifferent types using serving nodes of different structure such asMSC/VLR, RNC, clustered network elements etc.

1-23. (canceled)
 24. System including a first entity for transmittingdata packets and/or signalling to another entity or receiving datapackets and/or signalling from the another entity, the first entityhaving a distributed architecture which includes at least two processingunits each having their own address or identifier and being able totransmit and/or receive packets and/or signalling to or from the anotherentity, the first entity being adapted to send, in case one or more ofits processing units has become at least temporarily unusable, or is atleast temporarily not to be used, for sending or receiving packetsand/or signalling, information to the another entity for informing theanother entity thereon, wherein the first entity maintains in aprotected memory the addresses of all said another entities it isconnected to, and is adapted to send, in case one or more of itsprocessing units has become at least temporarily unusable, or is atleast temporarily not to be used, for sending or receiving packetsand/or signalling, information to all said another entities stored inits said memory, for informing the another entities thereon.
 25. Systemaccording to claim 24, wherein the address is an IP address.
 26. Systemaccording to claim 24, wherein the identifier is a Tunnel EndpointIdentifier (TEID).
 27. System according to claim 24, wherein theidentifier is a logical name, and this logical name is exchanged betweensaid first and another entity during connection creation ormodification.
 28. System according to claim 24, wherein the first entityis a GTP entity.
 29. System according to claim 24, wherein the firstentity is a support node, preferably a GPRS support node, preferably aSGSN.
 30. System according to claim 24, wherein the another entity is anode, preferably a support node, preferably a GPRS support node,preferably a GGSN.
 31. System according to claim 24, wherein theinformation sent from the first entity to the another entity is a GTPmessage.
 32. System according to claim 24, wherein the information sentfrom the first entity to the another node contains the address of theprocessing unit which is at least temporarily unusable or not to beused.
 33. System according to claim 24, wherein the information sent tothe another entity includes the identifier of the unusable processingunit(s) which is at least temporarily unusable or not to be used. 34.System according to claim 24, wherein the information sent to theanother entity includes the address of the first entity and theidentifier(s) of the unusable processing unit(s).
 35. System accordingto claim 24, wherein the information sent from the first entity to theanother entity contains indication of another processing unit to be usedfor receiving and transmitting packets and/or signaling instead of theprocessing unit having become at least temporarily unusable.
 36. Methodfor handling data packet transmission and/or signalling in a systemincluding a first entity for transmitting data packets and/or signallingto another entity or receiving data packets and/or signalling from theanother entity, the first entity having a distributed architecture whichincludes at least two processing units each having their own address oridentifier and being able to transmit and/or receive packets and/orsignalling to or from the another entity, the first entity sending, incase one or more of its processing units has become at least temporarilyunusable, or is at least temporarily not to be used, for sending orreceiving packets and/or signalling, information to the another entityfor informing the another entity thereon, wherein the first entitymaintains in a protected memory the addresses of all said anotherentities it is connected to, and sends, in case one or more of itsprocessing units has become at least temporarily unusable, or is atleast temporarily not to be used, for sending or receiving packetsand/or signalling, information to all said another entities stored inits said memory, for informing the another entities thereon.
 37. Methodaccording to claim 36, wherein the address is an IP address.
 38. Methodaccording to claim 36, wherein the identifier is a Tunnel EndpointIdentifier (TEID).
 39. Method according to claim 36, wherein the firstentity is a GTP entity.
 40. Method according to claim 36, wherein thefirst entity is a support node, preferably a GPRS support node,preferably a SGSN.
 41. Method according to claim 36, wherein the anotherentity is a node, preferably a support node, preferably a GPRS supportnode, preferably a GGSN.
 42. Method according to claim 36, wherein theinformation sent from the first entity to the another entity is a GTPmessage.
 43. Method according to claim 36, wherein the information sentfrom the first entity to the another node contains the address of theprocessing unit which is at least temporarily unusable or not to beused.
 44. Method according to claim 36, wherein the information sent tothe another entity includes the identifier of the unusable processingunit(s) which is at least temporarily unusable or not to be used. 45.Method according to claim 36, wherein the information sent to theanother entity includes the address of the first entity and theidentifier(s) of the processing unit(s) which is at least temporarilyunusable or not to be used.
 46. Method according to claim 36, whereinthe information sent from the first entity to the another entitycontains indication of another processing unit to be used for receivingand transmitting packets and/or signalling instead of the processingunit having become at least temporarily unusable.